http://repositorio.ufc.br/handle/riufc/429 Mon, 17 Aug 2026 05:22:05 GMT 2026-08-17T05:22:05Z http://repositorio.ufc.br/handle/riufc/87046 Título: Optimization of the extraction and purification process of R-phycoerythrin from the macroalgae Solieria filiformis Autor(es): Lima, Raíssa Magalhães Ferreira Abstract: R-Phycoerythrin (R-PE) is a high-value biomolecule found in red algae (Rhodophyta), which acts as an accessory photosynthetic pigment and has gained importance in many biotechnological applications. Solieria filiformis, a species of Rhodophyta, has attracted attention due to its high content of phycobiliproteins, particularly R-PE. This work proposes to evaluate the effect of grinding time, solid-liquid ratio, and extraction time on the yield and purity index (PI) of R-PE extracted from Solieria filiformis, and to determine the optimized solid-liquid extraction conditions for R-phycoerythrin using Face-Centered Composite Design (FCCD), response surface methodology (RSM), and desirability function optimization (DFO) methodology, in addition to purifying the extract obtained by anion exchange chromatography. Solid-liquid extraction of R-PE was performed using 25 mM potassium phosphate buffer solution (pH 6.5) with different combinations of grinding time (2, 4, 6 min), solid-liquid ratio (SLR) (1:2, 1:3, 1:4 (w/v)), and extraction time (2, 4, 6 h), as determined by FCCD. This study confirmed the influence of grinding time and extraction time on the R-PE yield in the solid-liquid extraction process from S. filiformis. The optimized conditions predicted by the model equation for R-PE yield were 6 minutes of grinding time, SLR 1:2, and 4.2 hours of extraction time. The influence of grinding time on the R-PE PI was also confirmed, with the optimized conditions predicted by the model equation for R-PE yield being: 2 minutes of grinding time, SLR 1:3.64, and 2.4 hours of extraction time. DFO determined the conditions for multivariate optimization, which were: 6 minutes of grinding time, SLR 1:4, and 3.6 hours of extraction time. The purification methodology applied in this study allowed the recovery of 24% of the initially extracted R-PE with a PI of 2.92. The study generated a mathematical model for each evaluated response, and each model can be used to determine R-PE extraction conditions according to the protein application purpose. Tipo: Dissertação Wed, 01 Jan 2025 00:00:00 GMT http://repositorio.ufc.br/handle/riufc/87046 2025-01-01T00:00:00Z http://repositorio.ufc.br/handle/riufc/86913 Título: Modelagem totalmente implícita de poços na simulação composicional de reservatórios de petróleo Autor(es): Pereira Filho, Francisco Mauro Teixeira Abstract: This study aims to implement and evaluate the effects of implicit well modeling in fully implicit compositional reservoir simulation, considering different grid types, including structured grids—Cartesian and corner-point—and unstructured grids, combined with the finite volume method. The fully implicit modeling of production wells was implemented and tested in the UTCOMPRS compositional simulator, developed at the University of Texas at Austin, using the Peng-Robinson equation of state to describe hydrocarbon phase behavior. The study accounted for the interaction between wells and the reservoir by integrating the well equations with the reservoir equations. This approach allowed wells to operate not only under a prescribed oil flow rate but also under a prescribed total liquid flow rate, while also enhancing the physical accuracy of production rate estimations and improving computational efficiency compared to the semi-implicit model (the original simulator model), particularly when refined grids were used. Unlike traditional methodologies in UTCOMPRS, which use pressure, phase saturation, mole numbers, and bottom-hole pressure from the previous iteration to calculate well production rates, the proposed approach evaluates the well simultaneously with the reservoir variables. This enables the consideration of the well- reservoir pressure gradient and the fluid column weight along the completions. The Newton-Raphson method was employed to solve the nonlinear system resulting from this fully implicit formulation. The results indicated a significant reduction in the number of iterations, particularly for an anisotropic reservoir using a corner-point grid with 14 production wells, which achieved a 64.72% reduction in iterations compared to the semi-implicit model, leading to a 10.5-hour decrease in simulation time. Additionally, a maximum absolute average relative deviation of 1.48% was observed in gas flow rate compared to the commercial simulator used. Finally, the results highlight the importance of the well-reservoir pressure gradient in flow rate estimation, especially in scenarios with multiple wells and heterogeneous permeability fields. Tipo: Dissertação Wed, 01 Jan 2025 00:00:00 GMT http://repositorio.ufc.br/handle/riufc/86913 2025-01-01T00:00:00Z http://repositorio.ufc.br/handle/riufc/86855 Título: Estudo da degradação de peneiras moleculares no processo de secagem de gás natural utilizando TSA Autor(es): Cordeiro, Rebecca Cristina Galvão Abstract: Zeolites 4A (LTA) and chabazite (CHA), employed in natural gas dehydration by temperature swing adsorption (TSA), were evaluated regarding their structural stability and adsorptive performance after accelerated aging. The study aimed to correlate thermal degradation, water adsorption capacity, and carbonaceous deposition under conditions representative of industrial regeneration over hundreds of cycles. Adsorption isotherms, kinetic modeling using the linear driving force (LDF) model, textural characterization, and elemental analysis (CHN) were performed. A progressive reduction in equilibrium adsorption capacity (qₘ) was observed with aging, decreasing from 7.9 to 4.0 mmol g⁻¹ for CHA and from 12.3 to 10.8 mmol g⁻¹ for LTA. In contrast, the kinetic coefficient () remained nearly constant, indicating that mass transfer did not constitute the rate-limiting mechanism within the investigated range. CHN analysis revealed progressive coke accumulation, reaching 8.9 wt% for CHA and 1.9 wt% for LTA after 400 cycles, consistent with the reduction in micropore volume. The results demonstrate that the loss of adsorptive performance is predominantly associated with progressive textural degradation and carbonaceous deposition. This work combines, after accelerated aging over hundreds of TSA cycles, detailed textural characterization with a systematic evaluation of the kinetic coefficient for all samples, establishing an integrated correlation among aging, diffusion, and adsorptive response. This approach provides support for predicting the end of service life of molecular sieves, increasing the reliability of natural gas dehydration processes, and guiding the selection of more resistant materials for TSA units. Tipo: Dissertação Thu, 01 Jan 2026 00:00:00 GMT http://repositorio.ufc.br/handle/riufc/86855 2026-01-01T00:00:00Z http://repositorio.ufc.br/handle/riufc/86643 Título: Imobilização da anidrase carbônica de Sulfurihydrogenibium azorense no suporte a base de sílica SBA-15 com poros expandidos para captura de CO 2 Autor(es): Barboza, José Anderson Lucas Abstract: The increase in carbon dioxide (CO 2 ) emissions, mainly from the use of fossil fuels, has intensified the search for sustainable technologies aimed at mitigating environmental impacts, such as global warming. In this context, biological carbon capture and storage processes have stood out due to their higher selectivity and operation under mild conditions, reducing energy consumption compared to conventional methods, such as chemical absorption. Therefore, this work aimed to evaluate the immobilization of carbonic anhydrase, derived from the heterologous expression of the ArticExpress (DE3) strain of the thermophilic microorganism Sulfurihydrogenibium azorense, on mesoporous silica SBA-15 (Santa Barbara Amorphous-15) with expanded pores, aiming to obtain a biocatalyst with higher stability and efficiency for CO 2 capture. For this purpose, the enzyme was expressed in Escherichia coli, extracted by cell lysis, and analyzed in terms of catalytic activity and zeta potential. The SBA-15 support with expanded pores was synthesized via a hydrothermal route and characterized by nitrogen adsorption/desorption isotherms, Fourier-transform infrared spectroscopy, and point of zero charge, resulting in the formation of a structure with ordered pores. Meanwhile, for the biocatalyst obtained by physical adsorption (SBA-AC), the effects of pH, ionic strength, protein load, and contact time during immobilization were measured. Protein yields were higher than 90% under almost all conditions, indicating strong affinity of the enzyme extract for the support, and the condition of 50 mg of protein per gram of support showed the best overall performance, with recovered activity above 80%. In addition, the support not only promoted enzyme immobilization but also provided partial purification of the extract, selectively retaining carbonic anhydrase over other proteins present. Furthermore, the storage stability of SBA-AC biocatalysts and those chemically modified with glutaraldehyde (SBA-AC-GA) was monitored over 90 days, showing not only maintenance but also an increase in catalytic activity during this period, with an approximate 25% increment in relative activity for both cases. Therefore, the results of this work demonstrate that the immobilization of carbonic anhydrase on SBA-15 with expanded pores is a promising strategy for CO 2 capture, presenting high catalytic performance and elevated storage stability. Tipo: Dissertação Sat, 01 Jan 2028 00:00:00 GMT http://repositorio.ufc.br/handle/riufc/86643 2028-01-01T00:00:00Z